A Coulter EPICS-V fluorescence-activated cell sorter is requested. This instrument permits separation of dissociated cell suspensions into pure populations of homogeneous cells, provided suitable fluorescent labels are available. Such labeling will be achieved by retrograde transport of fluorescent dyes or by labeling with specific antibodies. The cell sorter will be used in a series of studies of the vertebrate nervous system to produce purified populations of various classes of neurons. This approach will overcome one of the most serious obstacles to study of the nervous system at the cellular level--the great heterogeneity of cell types in nervous tissue. A second application of the instrument will be for selecting positive hybridoma clones in immunological studies of neuronal antigens. The projects involved will make use of biochemical, physiological, and neuroanatomical techniques. The research will be focused on three major areas: the mechanisms of processing of visual information in the central nervous system; the functioning of the autonomic nervous system; and the mechanisms underlying nociception or pain. All of the studies involved will provide data that are important for understanding and treating disorders of the nervous system.